WO 2012/098159 A2 discloses such a device and a method. This known battery detects the temperature of each battery cell by a fiber-optic sensor. This allows a large number of measurement points and a measurement which is not affected by EMC influences. The strain of the battery cells with charge and/or discharge current can be concluded from the temperature thereof, as a result of which the gradual deterioration of individual cells of the battery is identifiable.
However, this known device does not allow the measurement of the state of charge, i.e. the determination of the charge stored in the individual battery cells.